Project 4Runner

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By the end of November I had finally gotten everything back together in the engine bay and after test firing the engine I proceeded to clean up the wiring both in the engine bay and under the dash. The 4Runner came with a Flex-a-Lite dual electric fan kit installed but after cleaning up the wiring I could not get it to cycle when the engine reached operating temperature. Upon opening the fan controller I was convinced a new one was needed; the existing one looked badly corroded inside and one of the resistors looked burned.  After some searching I could replace just the interior electronics for a reasonable $25 from Summit Racing.  A few days I had the new circuit board and the electric fans were up and running.

With all the engine systems functioning it was time to get the truck aligned.  It was during this phase that we discovered all the front suspension bushings were shot.  I was really hoping to get some more miles out of the stock stuff so I could evaluate my eventual front suspension upgrades but fate was having none of that.  Comparing the cost of stock vs. upgraded parts It made sense at this time to upgrade the upper control arms.  I went with some Light Racing Adjustable Upper Control Arms I picked up from Fat Bob's Garage.  Besides their adjustability I liked the fact that the larger than stock upper ball joint would not start squeaking like the uniball control arm versions sold by other vendors. I went with completely new stock lower control arms on the bottom due to having a hard time sourcing just the bushings. 

While I like to do this kind of work myself, I was short on time so the 4Runner was at a local shop for this portion of the project.  Realistically it would have taken me a week or so to gather all the parts and another weekend or two to completely rebuild the front end VS. 1 day at the mechanics. While the Runner was in the shop it was determined the rebuilt steering rack was in need of another rebuild and at least one new tie rod so we threw that onto the bill.  All told I was into the front end for another $1600 when all was said and done. This would explain why there were so many 4runners around the 250k mark for sale, seems like about that time you either sink the money into it or sell it. 

The shop also scanned all the codes and determined the MAF sensor was triggering the check engine light so I found a used on one E-bay for $40 and another week went by before I received and installed it.  You can really start to see how shipping times really drag out a project but the alternative of paying $700 for a new MAF sensor from the dealer just wasn't worth the time savings.

The maiden voyage went pretty well although the check engine light made another appearance.

My list of bad issues after the trip :

All the doors rattle and it appears as if there is no adjustment, just worn latches in the doors.

One of the rear drum brakes was rubbing on the new pads. We had a hard time getting that particular one on so I wonder if the ID was not machined correctly?

Like I mentioned, check engine light which made the truck run in safe mode; so it smelled rich and was down on power.

Rear suspension sucks, seems like the rear bump stops in the coils are way too long.  I am sure the leaking Bilstein's are not helping matters.

The good:

I was pleasantly surprised the truck climbed as well as the Jeep did; before hitting the dirt I was fairly convinced the IFS was going to be a detriment off-road but I honestly could not tell the difference. The Runner felt narrower than the LJ did off-road which is good considering some of the shelf roads we traversed. I would have liked a slightly lower gear for some of the more technical spots on the trail but power was fine when in low range. 

Upon getting back into town we had the codes read, they indicated a problem with the knock sensors (both banks).  Now I know the previous owner had replaced those so after some more digging I was pretty sure it was the knock sensor wiring harness which is prone to failure due to it being located in the oven like space under the intake manifold. Sadly this meant I had to take the engine apart down to the cylinder heads again to replace the $30 wiring harness.

The knock sensors are located inside the engine valley on the 3.4l, one below each cylinder head roughly centered up.  When the intake manifold is placed over the valley you are left with no way for air to flow thru that area. The pictures above show the intake manifold installed with the knock sensor wiring harness snaking out from under the coolant intake.

While removing the fuel injector rails I noticed one of the injectors was cracked.  Turns out these are modified Ford injectors that came with a URD fuel upgrade kit so they are not available off the shelf.  I ended up using JB weld to patch the injector tip which is really a removable plastic tip. While re-assembling the engine I also replaced the passenger side exhaust manifold gasket along with all the exhaust flange gaskets since most of the TRD gaskets seemed to be blown out.

I wasn't sure what I wanted to do with the rear suspension yet so to tied us over I replaced the worn out Bilstein shocks with a pair of Gabriel heavy duty shocks I picked up from Rockauto.  These were listed as a closeout item and were a very reasonable $18 each. The ultimate goal is to get some sort of reservoir shock installed out back along with and adjustable front coilover for the front so I can lower the ride height slightly.

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